The electrocardiographic signs of left complete bundle-branch block are now well established, and in the majority of cases they correspond to total or subtotal destruction of the left bundle-branch fibres (Lenegre, 1957). However, two sorts of problems remain under discussion, namely, demonstration of the left ventricular delay in atypical cases of left bundle-branch block, for example when left bundlebranch block masquerades as right bundle-branch block (Richman and Wolff, 1954), and demonstration of the type of disturbed left intraventricular conduction, whether bundle-branch or arborization block, in typical cases with abnormal QRS prolongation (Grant and Dodge, 1956).In a previous paper one case of intermittent left complete bundle-branch block was reported, which offered the opportunity to recall the signs of left ventricular delay, derived from the phonocardiogram and mechanocardiogram, i.e. indirect carotid pulse curve and apex cardiogram (Baragan et al., 1967). The purpose of the present study was to analyse the heart sounds and the mechanocardiographic curves of a relatively large number of chronic cases of left complete bundle-branch block, with the hope that they may help to answer, in the future, the two sorts of problems mentioned above. PATIENTS AND METHODThe group consisted of 30 clinical cases of miscellaneous heart diseases, the electrocardiograms of which met the classical criteria for left complete bundle-branch block, namely, a QRS complex of supraventricular origin or more in lead V6. There were 20 men and 10 women with an average age of 48-5 years (range 18 to 78). The aetiological factors responsible for the heart condition associated with the pattern of left complete bundlebranch block were valvular heart disease (10 cases), ischaemic heart disease (6 cases), primary non-obstructive cardiomyopathy (6 cases), obstructive cardiomyopathy (3 cases), systemic hypertension (3 cases), and idiopathic left complete bundle-branch block (2 cases). Of these, 2 cases of left complete bundle-branch block resulted from operation, and one case, which had already a left complete bundle-branch block before operation, was aggravated by the latter. Of the 30 cases, 18 were in, or had just recovered from, cardiac failure.The electrocardiogram, phonocardiogram, indirect carotid pulse curve, and the apex cardiogram were recorded with a photographic 4-channel Hellige Multicardiotest. The phonocardiogram, dissociated into two frequency bands (low from 5 to 50, and high from 50 to 250 cycles per second), was recorded simultaneously with an electrocardiographic lead, and alternatively either with an indirect carotid pulse curve (capacitance transducer Infraton-E system) or with an apex cardiogram (piezo-electric crystal), the patient lying in the left lateral position. Records were taken at a paper speed of 50 mm. per second, with the vertical lines separated by intervals of 0-02 second.The following time intervals were measured ( Fig. 1
In this study, we tried to disclose certain electrocardiogram (ECG) criteria that might be useful in the classification of posteroseptal accessory atrioventricular pathways as right and left in patients with pre-excitation in whom the accessory pathway localization was verified by subsequent successful ablation. Twenty such patients with posteroseptal accessory pathways (mean age 34.9 ± 9.8; 11 male, 9 female) were included in the study. Localization of the accessory pathway was right posteroseptal in 13 (65%) and left posteroseptal in 7 (35%). Common to all these 20 patients with posteroseptal accessory pathways was a QRS polarity positive in lead L1 and negative in leads D3, aVL. In patients with right posteroseptal accessory pathways, QRS polarity was negative in lead V1 in all and positive in lead V2 in 90%. On the other hand, none of the patients with left posteroseptal accessory pathways showed negative QRS polarity in lead V1.In conclusion, these findings strongly suggest that in patients with pre-excitation, a QRS polarity negative in lead V1 and positive in lead V2 is an important surface ECG finding that signifies right-sided localization of a posteroseptal accessory pathway. In cases with left posteroseptal accessory pathways, QRS polarity in leads V1 and V2 has been found to be either biphasic or positive.
SUMMARYIn this report, we describe a case of sustained ventricular tachycardia of right ventricular outflow tract origin, induced by dobutamine infusion in a patient with symptomatic, frequent ventricular premature depolarizations but no documented clinical ventricular tachycardia. Radiofrequency catheter ablation abolished not only the ventricular tachycardia itself, but also the frequent ventricular premature depolarizations responsible for all the symptomatology. In conclusion, provocation by catecholamine infusion may have a place in the search for an alternative to antiarrhythmic therapy in patients with isolated, frequent and symptomatic ventricular premature depolarizations. (Jpn Heart J 1997; 38: 127-132)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.